Scapula fractures in complex shoulder injuries and floating shoulders: a classification based on displacement and instability

BACKGROUND: Scapula fractures with injuries of the Superior Shoulder Suspensory Complex are often referred to as floating shoulders. However, present studies do not allow comparative evidence on indication for surgical treatment mostly due to the lack of precise definitions and comparable classifications. The aim of this study was to retrospectively analyze common types of complex shoulder injuries and develop a feasible classification allowing a therapeutic algorithm. METHODS: The study group consisted of 107 patients with scapula fractures combined with ipsilateral injuries of the shoulder girdle treated in a single trauma center between 2003 and 2010. Three-dimensional computed tomography was analyzed for dislocation and instability and assigned to subgroups of a defined classification system. Clinical data was acquired from a previously established database of all patients treated for the diagnosis of a scapula fracture. RESULTS: Fifty-seven of 107 (53.3%) complex scapula fractures were non-displaced and stable representing Type A fractures. Depending on the fracture pattern, three subgroups were defined. Treatment of Type A injuries should be non-operative. Displaced fractures of the scapula with a stable shoulder girdle were considered Type B injuries and represented 18.7% of all fractures. Thirty fractures (28%) with an unstable shoulder girdle were classified as Type C injuries. Again, subgroups with common injury patterns were identified. For both groups, operative treatment is recommended. CONCLUSIONS: The described classification system is a proposal able to categorize complex shoulder injuries and allows a comparison of injury patterns in further studies.